Organic solvent soluble cellulosic film plasticized with glycol diglycolate



Patented July 16, 1940 ORGANIC SOLVENT SOLUBLE CELLULOSIC FILM PLASTICIZED WITH GLYCOL DI- GLYCOLATE William D. R. Straughn, Kenmore, N. Y., assignor to E. I. du Pont de Nemours &' Company, Wilmington, Del., a corporation of Delaware No Drawing. Application September 1, 1939, Serial No. 293,052

8 Claims. 106-40) This invention relates to plasticized organic derivatives of cellulose, especially sheet material and the like. More particularly, it appertains to compositions of matter comprising essentially cellulose acetate plasticized with glycol diglycolate,

the same being eminently suited for the manufacture of thin film such as sheet wrapping material.

Organic derivatives of cellulose, such as organic l0 solvent, soluble cellulose acetate, are not compatible with many of the plasticizers heretofore known and used in nitrocellulose compositions.

In fact, up to the present time relatively few compounds have been found to have the desired compatibility necessary to enable them to combine with these cellulosic materials to produce strong and flexible film of the thinness desirable for a sheet wrapping material. Furthermore, many of the compounds which do satisfactorily produce flexibility and toughness vadversely affect other properties of the film, such as transparency,

and are, therefore, unsatisfactory. In addition,

some of the compounds effecting favorable characteristics in freshly prepared film have only a 5 temporary effect, and as a result, the plasticized material upon standing gradually loses its flexibility and becomes brittle.

This invention had for an object the production of new compositions of matter suitable for the manufacture of permanently transparent, strong and flexible sheets or films, and the sheet material produced therefrom. A further object was to dry cast acetone soluble cellulose acetate into thin, strong, flexible sheets capable of retaining their physical and chemical characteristics. A general advance in the art, and other objects which will appear hereinafter, are also contemplated.

In the following description, general and specific, are disclosed certain embodiments of the invention and details of what is believed to be the best mode for carryingout the invention.

It has now been found that cellulose acetate and like organic derivatives of cellulose, when 5 combined with glycol di-glycolate, having the formula:

ible sheets, films, ribbons, filaments, and the like.

55 In a preferred embodiment of the invention,

cellulose acetate containing 56% combined acetic acid (22.5 parts), glycol di-glycolate (7.5 parts), and acetone (70.0 parts) were mixed together to form a solution. After being filtered and rested for a suitable period of time (usually 3 or 4 days 5 I to enable air bubbles to work out of the solution) in accordance with dry casting practice, it was dry cast upon a smooth nickel casting wheel (any other suitable film-forming surface may be em- 7 ployed) to produce a film in a manner well known 10 to those skilled in the art. The film so produced was transparent, strong and flexible.

This invention is applicable to all kinds 'of organic derivatives of cellulose which are soluble ,in organic liquids (solvents), including cellulose esters such as cellulose acetate, cellulose propionate, cellulose butyrate, and the like; mixed esters, such as cellulose aceto-propionate, cellulose aceto-butyrate and the like; cellulose ethers, such as methyl cellulose, ethyl cellulose, benzyl 20 cellulose and the like; mixed ethers, such as ethyl-benzyl cellulose and the like; and mixed cellulose ether esters such as ethyl cellulose acetate, and the like.

Any suitable solvent for the composition may 25 Ethylene dichloride-methanol 90:10 Methylene dichloride-methanol 90:10 Methylene dichloride-ethanol .-90:10 Methylene dichlorlde-isopropanol 90:10 Methyl acetate and 5 Ethyl formate.

Inpractlce the glycol di-glycolate is incorporated in the cellulose acetate and like material to the extent of from about 10% to 40% (based on the weightof the solid product formed). Preferably the formed product contains about 10% .to 25% of the plasticizer. col di-glycolate is especially useful for softening and/or plasticizing acetone-soluble cellulose acetate suchi-as that containing from 51%-56% (or more 46%-56%)- combined acetic acid.

The glycol di-glycolate may be used in the cellulose derivative composition alone or in combination, with other known plasticizers, such as, for example, ethylene glycol mono-methyl ether adipate, ethylene glycol mono-methyl ether phthalate, ethylene glycol mono-ethyl ether phthalate, ethylene glycol mono-butyl ether phthalate, triethylene glycol, tetra-ethylene glycol, diethylene glycol isobutyrate, di-ethylene glycol di-propionate, tri-ethylene glycol hexoate, octyl glycolate, dimethoxy tetraethylene glycol, and the like. Theadjuvant plasticizer material may comprise one or more than one of these substances.

The composition, although comprising essentially cellulosic material (the organic derivative of the cellulose) and plasticizing material, may, if desired, contain in addition natural or synthetic resins, waxes, dyes, blending agents, and the like, or even pigments or other opaquing agents.

Although this invention has been described primarily from the standpoint of the manufacbroadly,

ture of sheeting or film for use as sheet wrapping material, these compositions may be used for the manufacture of photographic film, plastics, lacquers, artificial straw, fine filaments and yarns thereof suitable for textile uses, and other products.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited.

to the specific embodiments thereof except as defined in the appended claims.

' I claim:

1. A composition of matter consisting of organic solvent solublecellulose acetate plasticized with 10% to 40% (based on the weight of the combination) of glycol di-glycolate.

2. Sheet wrapping material consisting essentially of cellulose acetate plasticized with glycol di-glycolate.

3. A composition of matter consisting essentially of cellulose acetate plasticized with onethird its weight of glycol di-glycolate.

4. A third film comprising essentially cellulose acetate of about 56% combined acetic acid con- .tent and 10% to 40% (based on the weight of the product) of glycol di-glycolate.

5. Sheet wrapping material comprising essentially cellulosic material which is organicsolvent soluble and which is from the group consisting of cellulose organic acid esters and cellulose ethers plasticized with glycol di-glycolate.

6. Sheet wrapping material consisting essentially of organic solvent soluble ethyl cellulose plasticized with glycol di-glycolate.

7. A composition of matter consisting of organic solvent soluble cellulose acetate plasticized with 10% to (based on the weight of the combination) of glycol di-glycolate.

8. A composition of matter consisting of organic solvent soluble ethyl'cellulose plasticized with 10% to 25% (based on the weight of the combination) of glycol di-glycolate.

WILLIAM D. R. STRAUGHN. 

